Device for ascertaining the expansibility and contractility of balance-wheels



(No Model.) 2 sheets Sheet 1.

J. LOGAN.

. DEVICE FOR ASCERTAINING THE EXPANSIBILITY AND CONTRACTIBILITY OEBALANCE WHEELS'POR WATCHES.

N0. 392,4 1? ented Nov. 6, 1888..

AWL NAA N. PETERS. Pholo-Lithvghphgr. Washinglcn, EC.

2 Sheets-Sheet 2.

(No Model.)

J. LOGAN. DEVICE FOR ASGBRTAINING THE EXPANSIBILITY AND GONTRAGTIBILITY01E BALANCE WHEELS FOR WATCHES.

Patented N.

N, PETERS. Flwio'Liulumpjm. Wuhingtnll D. C.

UNITED STATES PATENT rrrcn.

JOHN LOGAN, OF WALTHAM, MASSACHUSETTS.

DEVICE FOR ASCERTAINING THE EXPANSIBILITY AND CONTRACTIBlLITY OFBALANCE-WHEELS FOR WATCHES.

SPECIFICATION forming part of Letters Patent N 0. 392.442, datedNovember 6,1888.

Application filed February 23, 1888. Serial No. 264,986. (No model.)

To aZZ whom it may concern.-

Be it known that I, JOHN LOGAN, of Walthan], in the county of Middlesexand State of Massachusetts, have invented certain new and usefulImprovements in Devices for Ascertaining the Expansibility andOontractibility of Balance-Wheels for Watches, of which the following isa specification.

In the construction of balance-wheels for chronometers and the bettergrades of watches it is necessary, in order to secure accuracy ofmovement, to provide means for compensating for the disturbing influenceof varying degrees of temperature to which they may be exposed, theeffect of heat being to increase the length of the hair-spring and toweaken its elastic force, and the opposite result of course being theeffect of cold.

To provide means whereby the needful compensation aforesaid shall beautomatically performed, it is customary to construct the rim of thebalance of two metals, the outer portion of which shall possess thequality of high expansion under the influence of heat. The balance beingconstructed with two arms to support the rim and the rim being severedat opposite sides and at points adjacent to the supporting-arms, the rimis thus formed in two sections, each of which is supported at one endonly, leaving the other end free to yield and move from its normalposition in either direction as they are subjected to the influence ofheat or cold. It will be readily seen that the point of greatestmovement will be at the free end of each section of the rim, and that ifthe extent of movement of this free end of the rim from its normalposition can be measured or determined then the relative expansivequalities of different balances can be ascertained and the correspondingrequirements of the hair-spring determined.

The aim and object of my invention are to provide a device or improvedmeans for readily measuring the amount of expansion of watch orchronometer balances; and the invention in the present case consists ofthe devices which I will now proceed to describe and claim, referencebeing had tothe accompany drawings, and to the letters of referencemarked thereon, forming a part of this specification, of which drawings-Figure 1 is a top plan view of my contrivance for measuring theexpansibility and contractibility of balance-wheels for chronometers andwatches in one of the forms in which I have found it convenient toemploy it, the pointer being attached to one of the free ends of the rimand extending directly outward therefrom, a part of the handle orsupport being pictured as broken out. Fig. 2 is a side elevation of thedevice shown in Fig. 1. Fig. 3 is a top plan view of the balance-wheelsupport or clamp. Fig. 4 is a sectional detail view taken on the linewas of Fig. 3. Fig. 5 is a sectional detail taken on the line y y ofFig. 1. Fig. 6 is a detail view showing a modified manner of supportingthe pointer and connecting it with one of the free ends of the rim ofthe balance-wheel. Fig. 7 is a detail view showing the manner ofimmersing the holder and balance in water contained in a basin orvessel.

Like letters of reference designate like parts in all of the views.

In carrying out myinvention I provide suitable means for holding thebalance-wheel a in fixed position, so that its rim b shall be free toexpand and contract as it may be affected by heat and cold. The meansemployed for this purpose may be variously constructed. That here shownas employed for this purpose consists of a standard or post, 0, split atits upper end, as at d, and provided in its upper end or face with agroove or channel, 6, adapted to receive the cross-arm f of thebalance-wheel and to pinch and hold said cross-arm between the splitportions of the post by means of the thumb-screw g, passing looselythrough one of the slit portions and screw-tapped into the other, asshown most clearly in Fig. 4, where the balance-wheel-holding post isportrayed in inverted position.

The lower end of the post 0 is detachably secured in a clamp-collar, h,to which one end of a handle or rod, z, is secured in any suitablemanner, a graduated indicating scale or plate, j, being adj ustablyattached to said handle or rod toward the opposite end thereof.

It designates a finger or pointer, preferably composed of aluminum orother light metal, though it may be composed of any suitable material,which pointer is attached at one end IOO to or near to one of the freeends of the divided rim of the balance-wheel and has its other endextended out to or over the graduated plate or scalej, so that if thebalancewheel should be plunged or immersed in cool or ice-cold water thecontraction of the rim b would move the free end of the pointer 7.: inone direction on the graduated plate or scale, and if the balance-wheelshould then be immersed in hot or boiling water the expansion of the rimwould move the free end of the pointer in the opposite direction and thedegree of contraction and expansion of the rim accurately ascertained,so that balances which have not a sufficient expansibility andcontractibility can be rejected.

I have mentioned the plunging of the balance-wheel lixed upon itssupport firstin ice cold water and then in boiling water; but these twoacts maybe performed in reverse order, or other liquids may be used inplace of water, or other temperatures than ice-cold and boiling water,or the wheel subjected to varying temperatures in other ways with thesame resultas that described. I have foundit most expedient, however, toemploy water, since water under the conditions mentioned is at fixeddegrees of temperature and may be readily employed.

Though it is not essential, I prefer to make the scale or graduatedplate j adjustable lat orally as well as longitudinally with respect topointer 7;, so that when, say,the balancewhcel is immersed in ice-coldwater or liquid of a certain temperature (ascertainable with athermometer) the dial or plate may be adjusted so that thepointer 7.:will be at or pointto zero, (0,) and when the balance-wheel is immersedin boiling water or hot liquid of a certain temperature the pointer willmove from zero outward therefrom and show at a glance and withoutcomputation the degree of contraction or expansion under the two degreesof temperature. This lateral adjustability of plate j is here shown asaccomplished by arranging said plate on its support at so as that it mayslide thereon, arranging a rod, n, so as to turn in bearing formed inthe support m, but so as not to move longitudinally therein. Rod n isgiven a screw-thread connection with plate j. (llere shown as throughthe medium of :1 lug, 0, formed on the lower side of the plate.) When,new, rod a is revolved, which may be accomlished by means of athumb-knob, 1), on the end thereof, platej will be moved on its supportm, as described. The construction and operation just set forth will beclearly understood. by reference to Fig. 5 of the drawings.

11 designates a thumb-screw, by means of which the support in may beadjusted longitudinally 011 rod 2'.

1- designates a plate attached to the rod i, which may be employed toassist in maintaining the parts in proper position horizontally, andthis may be done by resting said plate on the edge of the vesselcontaining the water or other liuid in which the balaneewheel may beimmersed, lugs s on the lower face of plate r serving to engage the sideof the rim L of the vessel it, thus affording a rest for the plate 1',which will preventit from slipping forward off the rim into the vessel.

In Fig. (3 I have shown the pointer is as piv oted at its end adjacentto the balance-wheelsupporting means to the support for said means, asat 2, and as provided with a short angular arm, 3, the free end of whichengages one of thefree ends of the divided rim of the balance-wheel, sothat as said rim contracts and expands the pointer it will be moved onits pivot 2, and the free end of said pointermoved over the graduatedplate orsoalc, with the result before explained.

Though I have been particular to describe all of the parts of myimprovement as shown in the drawings, it is obvious that said parts maybe varied in form and arrangement without departing from the nature orspirit of the invention hereinbcfore and hereinafter set out.

The operation of my improved device will be readily understood. Abalance-wheel being fixed in position on the post c, one end of thepointer k may be attached thereto by passing said end into or throughone of the holes formed in the rim, or otherwise securing it thereto,the other end extending out over the graduated plate or scalcj, so thatthe balance-wheel. can be at once immersed in cold water or other liquidand the plate j adjusted as explained, when said balance-wheel can betaken out of the cold water and sub jected to hot or immersed inice-cold water, and the degree of expansion and contraction of the rimthus ascertained with the greatest accuracy.

I claim- 1. A device for ascertaining the expansibility andeontractibility of balance-wheels for watches, consisting of a supportfor the balance-wheel, a clamp connected with said support for holdingthe balance-wheel in fixed position, a graduated scale, and a pointerattached at one end to the rim of the balancewheel and having the otherend extended to or over the scale, as set forth.

2. A device for ascertaining the expansibility and contractibility ofbalanceavheels for watches, consisting of a support for thebalance-wheel, a clamp connected with said support for holding thebalance-wheel in fixed position, a graduated scale, a rod or barconnecting the support for the balance-wheel with the scale, and apointer attached at one end of the rim of the fixed balance-wheel, andhaving the other end extended to or over the scale, as set forth.

3. A device for ascertaining the expansibility and eontractibility ofbalance-wheels for watches, consisting of a clamp and support forclamping and holding the cross-arm of a balance-wheel in fixed position,a gradu- III) ated scale, and a pointer attached at one end to the rimof the balance-wheel and having the other end extended to or over thescale, as set forth.

4. A device for ascertaining the cxpansibility and contractibility ofbalance-wheels for watches, consisting of a support for thebalance-wheel, a clamp connected with said support for holding thebalance-wheel in fixed position, a graduated scale, and a pointerattached at one end to the rim of the fixed balance-wheel and having theother end extended to or over the scale, the said scale being adjustablelaterally with respect to the pointer, as set forth.

.5. A device for ascertaining the expansibility and contractibility ofbalance-wheels for watches, consisting of a support for thebalance-wheel, a graduated scale, a rod or bar connecting the supportfor the balance-wheel 2 with the scale, a supporting-plate on said rodor bar intermediate of the scale and the support for the balance-wheel,and a pointer attaehed at one end to the rim of the balancewheel andhaving the other end extended to 25 or over the scale, as set forth.

In testimony whereof I have signed my name to this specification,in thepresence of two subscribing witncsses', this 14th day of February, A. D.1888.

JOHN LOGAN.

Witnesses:

O. F. BROWN, E. A. MARSH.

